The present invention relates to so-called "aramid" fibers, that is to say fibers of linear macro-molecules made from aromatic groups joined by amide linkages at least 85% of which are joined directly to two aromatic rings and, more precisely, to aramid fibers made from optically anisotropic spinning compositions.
In known manner, aramid fibers of high strength and high modulus are characterized generally by fibrillation phenomena on the surface of their filaments and low resistance to abrasion. These weak points and/or certain processes for remedying them have, for example, been described in the case of conventional aramid fibers of small filament diameter in the following patents or patent applications:
EP-A-163,403, EP-A-332,919, U.S. Pat. No. 4,670,343, JP-A-01/85 3772, JP-A-63/243,330.
This fragility, which is harmful for certain properties of use of these fibers, may also be harmful to those of their assemblages or to those of the articles reinforced by these fibers or assemblages.
International application PCT/CH90/00155, incorporated by reference in the present application, describes aramid monofilaments having both a large diameter and high mechanical properties in the as-spun state.
However, these aramid monofilaments are, as a whole, subject to the same weaknesses as those described above. It was therefore clearly desirable to produce aramid monofilaments the resistance to fibrillation and abrasion of which is greatly improved.